Tooth whitening has become very popular over the past few years. More and more consumers are choosing to whiten their teeth. Options for tooth whitening include toothpastes, mouthrinses, chewing gums, in-office bleaching, and most commonly tooth whitening solutions used with a tray obtained either over-the-counter or from a dentist. The tooth whitening solutions contain an active ingredient which bleach the teeth. This solution is placed into a dental tray in which a patient wears to bleach his or her teeth. Typically, the oral composition comes in a squeeze bottle, tube, or syringe.
It is known that tooth whitening active materials may be difficult to keep stable for long periods of time. The most common dental bleaching agents are peroxides, which are known to be very reactive. To improve stability, a peroxide may be encapsulated, formulated in a two part composition, or stabilizers added to maintain peroxide levels. Generally, the peroxide compositions are stored in sealed, bulk containers, such as a syringe or tube.
Non-bulk, tooth whitening systems comprising a strip and a pre-dosed amount of a tooth whitening composition are described in U.S. Pat. Nos. 5,984,017; 5,879,691; 5,891,453; 6,045,811; and 5,989,569, the substances of which are fully incorporated herein by reference. These improved systems provide a disposable and more user friendly means for tooth whitening. However, the peroxide containing oral composition is more difficult to stabilize for extended periods of time because the oral composition is stored as a thin layer and not in a syringe or in bulk.